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Full text of "Treatise On Applied Analytical Chemistry(Vol-1)"

440

SPERMACETI

It gives stable mixtures or emulsions with large quantities of water (up to
more than 100%), and the fat mixed with 20-30% of water is given the
name Lanoline.

It dissolves little in cold alcohol and somewhat more in boiling absolute
alcohol; it is soluble in ether or chloroform, giving, however, turbid liquids
when it contains water. Its characters are indicated in Table XLIX.

When a solution of o-i gram of dehydrated lanoline in 5 c.c. of chloroform
is carefully poured on to 5 c.c. of cone, sulphuric acid, at the zone of contact
of the two liquids there is produced a bright brownish-red coloration, which
reaches its maximal intensity after 24 hours.

The most important tests to be made on lanoline, especially that for
pharmaceutical purposes, are :

1.  Water and Ash.—10 grams are heated  at 100-110° to  constant
weight, the residue being carefully incinerated and the ash weighed.

2.  Acidity.—As in General Methods, 7.

According to the Official Italian Pharmacopoeia, the test for acidity is
made by dissolving 2 grams of the lanoline in 20 c.c. of petroleum ether,
adding 2 drops of phenolphthalein solution and then 0-5 c.c. of decinormal
sodium hydroxide solution : the liquid should be coloured a persistent red.

3.  Other Tests.—The lanoline is heated with aqueous caustic soda
solution to ascertain if  ammonia is evolved.    10   grams of   lanoline are
heated on the water-bath with 50 grams of water :   a clear and slightly
coloured layer of fused fat should form at the surface of the water;  with
impure lanoline a brown, turbid and frothy mass is obtained.

*
* *

Pure anhydrous lanoline should contain only traces of moisture, and that
emulsified with water should contain not more than y. % of the latter. Further,
it should have little ash (at most 0-05%), give no acid reaction with litmus
paper, correspond with the Official Italian Pharmacopoeia test (-2), and give
no ammonia when heated with soda solution.

Spermaceti t

This is the solid portion obtained by cooling and pressure from the
oil contained in the cephalic cavity of the sperm whale or cachalot (Catodon
•macrocefihalus] and allied species.

Refined or pure spermaceti of commerce is in white, hard, crystalline
masses (thin sheets), slightly fatty to the touch and almost odourless; in
the air it becomes yellowish and rancid.

It dissolves in boiling alcohol, from which it crystallises on cooling, and
it is soluble also in ether, chloroform, benzene and carbon disulphide ; it
dissolves very slightly in cold 98% alcohol and is insoluble in 90% alcohol
or in water. Its physical and chemical characters are given in Table XLIX.

Spermaceti consists mostly of cetin (the cetyl ester of palmitic acid),
m.pt. 53-5°, and contains 50-52% of unsaponifiable substances.

Detection of Adulterants.—Additions of ceresine or solid paraffin,
stearic acid (stearine), tallow and beeswax are made, but only rarely, since
extraneous substances easily destroy the characteristic crystalline structure. if its characters are abnormal,